The disclosure concerns the use of “rich colored transition sequences” (RCTS) together with multi camera optical tracking within a 3D space for control of computer applications or measurement and collection of 3D data.
It has always been a dream in the machine vision community to track objects in 3D with a multitude of cameras. There is no end to applications that could benefit from seamless multi-camera optical tracking: gaming, robotics, medical care, surgery, home control, etc. Moore's Law is driving the price point and capability of computers, cameras, and communication to a point where this may soon be possible. Some of the barriers to widespread adoption are addressed here.
Usually the assumption is made that all positions in a 3D volume need to be visible to at least two cameras at all times. This leads to a complex optimization problem especially when people can move around the space and occlude some of the cameras. Implicit in this is the need to synchronize all of the cameras with overlapping fields of view.
The associated computational and mathematical problems grow dramatically as the number of cameras increase. Photogrammetry using two cameras was never easy but it gets much tougher when three or more cameras are used on the same field of view especially when some cameras see the object from a different side and angle, and lighting changes as clouds pass by, and people pass in from of cameras. The burden on computers can be horrific.
This method and apparatus, together with the three previous patents of the inventor extensively disclose how targets of color can be used to build fast, robust and inexpensive machine vision interfaces. The next three paragraphs below are a brief and incomplete summary of these three patents where many of the relevant elements of the past work is discussed.
U.S. Pat. No. 8,064,691, explains how colored targets could be composed of rich colors that were far more reliable in variable lighting environments. The rich color method was fast and would greatly benefit when future cameras move beyond the three RGB sensors of today.
U.S. Pat. No. 8,526,717, discloses how the method is greatly enhanced when the transition boundary curves that separate rich colored patches are used for tracking. The transition curves that separate rich colors rarely occur in a given image and if search is limited to a relatively small number of ordered adjacent sets of curves of a given shape bounded by specific color pairs, we have a robust, fast tracking method that requires little computer memory. This can easily be implemented in hardware or software of a smart camera. An example of an everyday smart camera is an iPhone or iPad where a software app could perform many tasks.
U.S. patent application Ser. No. 14/014,936, explains how a sequence of sub-targets that are arrayed along a roughly straight line path can provide an almost unlimited number of IDs. These sequences act as a single target which can be used to detect, ID, locate, and orient a rigid object to which the sequence is attached. Further, this patent shows how multiple cameras and computers can gather location and orientation data about each sequence and applications can be constructed in a modular fashion such that a pair of lists can control a wide set of machine vision applications. This so called “see-this” and “do-that” lists are all that are needed to pick an app and guide it's action.